Analysis of weather exposure 7 days before occurrence of ST-segment elevation myocardial infarction

Background: Several studies have highlighted the relationship between weather patterns and the occurrence of ST-elevation myocardial infarction (STEMI). Aim: To evaluate the statistical association between the occurrence of STEMI and meteorological variables over the preceding 7 days. Methods: This was a retrospective study, using prespecified data from the ORBI (Breton Regional Observatory on Myocardial Infarction) registry, which includes all consecutive patients hospitalized for STEMI in the geographical area of Brest, France. Over a 7-year period, we compared the number of STEMIs per week with the mean values of meteorological variables over the preceding 7 days. Results: Overall, 7517 patients with STEMI were recorded in the ORBI registry between January 2009 and January 2016. After exclusion of patients not living in the geographical area of interest, 742 patients were included. The weekly incidence of STEMI ranged from 0 to 7 (median 2, interquartile range 1–3). In the univariate analysis, air temperature (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.005–1.01 per 1 °C decrease; P = 0.03) and atmospheric pressure (OR 1.03, 95% CI 1.01–1.06 per 1 hPa increase; P = 0.008) were associated with the weekly incidence of STEMI. In the multivariable analysis, air temperature (OR 1.06, 95% CI 1.01–1.10 per 1 °C decrease; P = 0.01), atmospheric pressure (OR 1.05, 95% CI 1.02–1.08 per 1 hPa increase; P < 0.001) and duration of humidity > 80% (OR 1.09, 95% CI 1.02–1.15 per 1 hour increase; P = 0.007) in the previous 7 days were associated with the occurrence of STEMI. Conclusions: In this specific geographical area, occurrence of STEMI was statistically associated with a decrease in air temperature, an increase in atmospheric pressure and an increase in humidity over the preceding 7-day period.